Flotation apparatus



Sept. 23, 1969 Original Filed Dec.

R. D. HAWKINS 3,468,279

FLOTATION APPARATUS 29, 1965 4 Sheets-Sheet 1 ll/IIIIIV ljl/Il/ 11 All/II/Il/IIIl/II/IIIl/llll FIG. 2A FIG- 28 FIG. 2C

Sept- 3, 1969 R. D. HAWKINS FLOTATION APPARATUS 4 Sheets-Sheet 2Original Filed Dec. 29, 1965 Sept. 23, 1969 R. D. HAWKINS 3,468,279

FLOTATION APPARATUS Original Filed Dec. 29, 1965 4 Sheets-Sheet 5 [U DUIUU/ Sept. 23, .1969 R. D. HAWKINS FLQTATION APPARATUS 4 Sheets-Sheet 4Original Filed Dec. 29, 1965 United States 3,468,279 FLOTATION APPARATUSRobert D. Hawkins, 115 Stony Hollow Road, Greenlawn, N.Y. 11740 Originalapplication Dec. 29, 1965, Ser. No. 517,349, now

Patent No. 3,370,562, dated Feb. 27, 1968. Divided and this application.1211. 2, 1963, Ser. No. 694,612 Int. Cl. B631 1/38; B60v 1/04 US. Cl.11467 12 Claims ABSTRACT OF THE DISCLOSURE An air supported vessel foruse in water is described as having an open bottomed hull from whichthere is extended a movable partition or skirt member secured about theopening in the hull. This partition when extended upward gives thevessel desirable properties for mobility and when extended downwardgives the vessel desirable properties for station keeping.

Cross reference to related application Copending application Ser. No.517,349, filed Dec. 29, 1965 of which the present application is adivisional ap plication.

Background summary of the invention This invention relates in general tofloatable structures, and in particular provides an improved form ofhull therefore which works to stabilize itself in response to and as aresult of the very forces tending to unstabilize the hull.

Basically the invention provides an open inverted hull that so capturesa large volume of air (under relatively slight pressure, e.g., 0.6 psi.above atmospheric) between the water line and a deck supported by thehull that the center of gravity of the overall structure issubstantially well above the water line. While admittedly such aconfiguration is ordinarily considered unstable and will readily flipover and sink in response to even very slight forces acting thereupon,nevertheless by suitably designing the sides of the hull, the craftcenter of buoyancy can be constantly shifted with such forces-not in away that encourages flipping and ultimate sinking-but in a way thatcounteracts the tendency of the craft to invert. This aspect of theinvention will be described in detail later.

A second aspect of the invention relates to a form thereof which readilylends itself to such uses as sea platforms and the like, e.g. as isoften employed in off-shore drilling for oil. Typical of presentpractice here is to float a large platform structure to the anchoringlocation, and then at a time when the sea state is reasonably calm,jacking up the whole platform by means of expensively designed andcomplicated support legs, using the ocean floor as a base for the legs.Rather than adopt this conventional form of sea platform, the presentinvention proposes the use of a platform or deck supported by a hull asbriefly described above, but in which the hull may take the form of aremovable skirt, preferably of an elastic material for wave isolationpurposes. To the platform or deck, vertically positionable anchoringstilts are secured, whereby once the platform has been floated to itsanchoring location by means of the hull, and the stilts have beenlowered for anchoring and support purposes, the hull skirt may beevacuated or even removed to etfect a sea platform, and this withoutjacking equipment.

A third aspect of the invention relates to a presently preferred form ofhull skirt, i.e. one which is adjustable to accommodate difierentconditions of floatation, e.g. when the hull respectively is and is notbeing driven across the surface of the sea. As to this third aspect ofthe in- "ice vention, the hull skirt is provided with an extendableportion which when extended into the water increases the verticaldimensions of the hull and prevents leakage of the captured volume ofair. For hull mobility however the extendable hull position may beraised to a shallow depth to prevent drag, and to encourage planing.

A principal object of the invention is to provide an improved form ofhull design.

Another object of the invention is to provide a floatable structure thatis supported by a captured volume of air.

Another object of the invention is to provide a floatable structurehaving a center of gravity above the water line and an inverted openhull having sides so disposed that the center of buoyancy of thestructure always positions to counter any tendency of the hull toinvert.

Another object of the invention is to provide a floatable structurehaving an inverted open hull and a deck supported by the hull, such hullbeing removably secured to the deck.

Another object of the invention is to provide an improved hullconfiguration that not only is exceedingly stable, but which alsoisolates members supported by said hull from wave disturbances and thelike.

Another object of the invention is to provide an inverted open hullstructure, the vertical dimensions of which are adjustable for differentconditions of flotation.

The invention will be described with reference to the figures wherein:

FIG. 1 is a schematic presentation of one embodiment of the invention,

FIGS. 2A through 2D are diagrams useful in describing the concepts ofthis invention,

FIG. 3 is a view showing a presently preferred hull design according tothe invention,

FIG. 4 is a view showing .a feature of interest that is employed in thepresently preferred hull design of FIG. 3,

FIGS. 5 and 6 depict the presently preferred hull respectivelystationary and moving,

FIGS. 7 through 10 show how a hull according to the invention may beemployed to effect a sea platform,

FIG. 11 is a view showing a boat-supporting stilt as may be employedwith the invention, and

FIG. 12 is a sectional view showing another embodi ment of theinvention.

Referring to FIG. 1, the presently preferred embodiment of the inventionis shown having a deck 10 with an opening 12 therein. The deck 10 ispreferably of a material that is impervious to air. An air pump 14(which preferably is automatically controlled with respect to a pressurereference as is well known in the art) within a walled compartment 16 isadapted to blow air into a chamber 18, the sides of which constitute anopen inverted hull 20. The hull 20 is secured to the deck 10 in as closeto an airtight manner as possible, and as required for the principalfeature of the invention, the sides of the hull 20 make an acute anglewith the normal water line 21, being of such form that the sidespreferably gradually become more and more acute with respect to thewater surface. This latter aspect is desirable since gradually slopingsides compromise between those which are strictly vertical (forvirtually complete isolation against the vertical force of waves) andthose which are strictly horizontal (ideally the most preferable forstability purposes). The compartment 16 in which the blower 14- containsis provided with a valve 22 that may be adjusted by means of a stemmember 24 to exhaust air from the interior of the hull chamber 18. Thedeck 10 so supports a network of cabins 26, having a topside deck 28,that the craft center of gravity, C.G., is substantially well above thenormal water line 21. The water line 29 Within the open hull 20 is wellbelow the line 21 because of air pressure within the hull chamber 18.The motor 3 30 for propelling the craft secures to and is rigidlysupported by the deck 10.

Reference should now be had to the series of illustrations thatconstitute FIG. 2, whereby an explanation is given as to why a craftemploying the instant techniques has been found to be extremely stable.First off, illustra tions A and B, while depicting an open inverted hullthat is not in conformity with the invention, are nevertheless useful inemphasizing the concepts of the invention. In FIG. 2A a craft withvertically sloping hull sides 20 is shown in level attitude, its centerof buoyancy being on the same vertical as its center of gravity. With aslight unsettling force applied to the craft (FIG. 2B), it starts torotate about its center of gravity, whereby the captured volume of waterX is pushed rightward (looking at FIG. 2B) by the sides of the hull 20,.Hence, it is seen that the craft center of buoyancy (i.e. the center ofgravity of the displace volume of water) is shifted rightward as thecraft rotates about its own center of gravity, with attendantly thecraft flipping over and sinking like an inverted water glass in a tub ofwater.

Consider now a hull according to the invention (FIG. 2 illustrations Cand -D), viz one with hull sides that slope acutely into the water.Here, when the craft is forced from a level attitude (FIG. 2C) to thatshown in FIG. 2D, the captured volume of water X and the craft center ofbuoyancy are moved-not rightwardbut leftward. This can be appreciatedfrom the FIG. 2D which shows the left side of the sloped hull 20entering and scooping (not pushing) the captured water X whereby thecenter of buoyancy shifts leftward. As far as the righthand side of thehull 20 is concerned, this (because of its slope) cuts through the waterlike a knife edge, and therefore never pushes on the water. In otherwords, the water adjacent to the right hand side of the hull spills offsuch side and, in bootstrap fashion, flows onto the lefthand side of thehull. Since the craft center of buoyancy moves leftward as the lefthandside of the craft tends to sink deeper into the water, a stabilizingcounterforce is created by the craft itself, whereby the craft attitudeis kept level, a principal object of the invention being thus obtained.

Reference should now be had to FIGS. 3 and 4 which together show thedetails of a presently preferred form of hull design. A resilient (hull)skirt 40', as might for example be formed from rubberized nylon, securesto the deck by means of bolts 42 in sufliciently airtight manner. Wheninflated, the hull balloons outward so that its part 44 acutely cuts thewater, such ballooning being made possible by means of plural hullsupport poles 46 which are stationed generally circumferentially withinthe interior of the hull. Each pole 46 at one end secures to theunderside of the deck 10' by means of a flexible coupling 48, and thecouplings 48 in combination with the flexible hull itself substantiallyeliminate any tendency of the craft to respond to high frequency wavedisturbances. Each pole 46, at its other end, secures to the hull skirt40; in addition, respective cables 50 secure those support pole ends tothe deck 10'. The walls of the hull 40 are thus prevented fromsubstantial lateral motion as the hull is inflated, whereby the hullpart 44 is forced to assume an acute relationship with the line of thewater.

As shown in FIG. 4, the hull part depicted within the dashed line 52 ofFIG. 3 has a cable 54 that secures within a substantially airtightjuncture 55 of the hull part 44 and a hull part 56. In the hull regions58, the support poles 46 are adapted to be pivotally secured. A weightedring 60 so secures to the base of the hull part 56 that that partordinarily extends into the water. If desired, the part 56 may be raisedby means of cables 62 that are spatially aligned with the poles 46 andthe cables 50. That is, the extendable hull part 56 may be raised intothe interior of the hull 40, and against the weight of the ring 60, byhooking the cables 62 to respective hasps 64 fixedly located on thecables 50. Hasps 66 are provided to secure the cables 62 to prevent themfrom damaging the hull when the part 56 is extended; and similarly thecables 50 may be covered at 68 by suitable material to prevent them fromwearing the hull part 56 when that part is secured within the hullinterior.

FIGS. 5 and 6 diagrammatically show (without unnecessary detail) themodes of flotation when respectively the craft of the instant inventionis adapted for use as a sea platform, and for substantial mobility withminimal drag.

In FIG. 5, the vertical dimension of the hull has been extended as forexample when the internal hull cables 62 secure to the hasps 66. Asnoted above, this is the sea platform mode and has the advantages ofbeing least susceptible to the loss of air from within the hull chamber18. That is, for air to escape from within the hull of FIG. 5 as aresult of rolling (or pitching), would require the roll angle to be inexcess of the angle 5, an essentially remote possibility as discussedabove re FIG. 2. (Were the angle of roll to be greater than the angle1:, however, the air pump 14 would quickly replace the quantity of lostair.) In addition, when the sea state is such that the hull sits atopthe crests of, for example, a pair of waves, the extended hull portion56 assures that there is minimal loss of air, i.e. the opening in thehull bottom is always immersed.

In FIG. 6, the vertical dimension of the hull 20 is shown shortened, asfor example by securing the internal hull cables 62 to their respectivehasps 64; in addition, the hull is here presumed propelled in adirection D. By raising the hull part 56 substantially out of the water,drag obviously is kept minimal, a first effect necessary to goodmobility. Secondly, because of such relatively high mobility, the crafthas an improved tendency to plane (further decreasing drag), and toassist such planing the raised part 56 itself contours to augment thelift forces on the craft. See FIG. 6 which shows the lift force F actingon the craft bow, and created as the craft cuts through the water W Asmall aft lift force F results from water W within the raised part 56continually washing against that part. When moving, the craft of FIG. 6rides well out of the water drawing less than 10 inches of water thoughweighing 60,000 pounds.

With reference to FIGS. 7 to 10, the sea platform feature of theinvention will now be described. FIG. 7 shows the instant boat prior tolaunching, standing (on circumferentially located stilts to be describedpresently) near the shore line, at low tide, and with the resilient hull40 completely deflated. The stilts 80 (see FIG. 11) each comprise ahollow casing 82 having a weighted telescoping leg member 84. The member84 secures by means of a hook 86 to a nylon cable 87 that winds on awinch 88. The winch 88 is provided with a crank 90 having a coopcratinghandle 98 that may be slidably locked in a casing hole 92 to hold theweighted leg member 84 in place against its downward force. Secured tothe casing 82 is a leg clamp 94 having a hole 96 that is slightly largerthan the outer diameter of the leg member 84, and which leg member isslidably contained in the hole 96. Looking the leg member 84 againstupward movement is attained by the natural wedging of the leg member 84against the sides of the hole 96 in response to an off-axis upwardforce. Universally pivotally secured to the end of the leg member 84 isa foot piece 98 which is adapted to orient in accordance with thefooting.

As the tide moves in, the hull 40 of the unlaunched boat submergespartially, thereby trapping some air within the chamber portion 18 andreadying the hull 40 for flotation, which fact is achieved by turning onthe pump 15 (FIG. 1) and causing the hull 40 to balloon as shown in FIG.8. With the hull sides ballooned, the stilt legs 84 are raised by meansof the winches 88 and their cooperating cranks 90 (FIG. 9), whereby theboat becomes mobilely floated on the captured volume of air within itschamber 18. See FIG. 6. At the anchoring location, the stilt legs 84 arelowered, by releasing the Winches 88 from their respective lockedpositions, whereby the boat becomes fixedly supported by means of itsstilts 80, the feet pieces 98 of the stilts 80 assuming the contours ofthe ocean floor. Now the hull skirt 40 may be deflated, by opening theexhaust valve 22, after which time the hull may be removed from its deck(see FIG. 10), thereby effecting a sea platform that is clear of tides,waves, etc., without need for jacking equipment, a principal object ofthe invention being thus achieved.

While the invention has been described in its presently preferred forms,it is to be realized that the words which have been used are words ofdescription rather than of limitation, and that many changes to theinstant embodiments may be made without departing from the true scopeand concept of the invention. For example, it would be well within thepurview of the invention to employ a doughnut-shaped hull, cross sectionof which is shown in FIG. 12. The parts depicted on FIG. 12, whichrelate to respective parts of FIGS. 1, 3, etc., have the same referencecharacters as indicated on those figures but to distinguish the FIG. 12characters, primed notations have been employed.

What is claimed is:

1. Floatable apparatus for use on bodies of water comprising an openbottomed hull and a deck supported thereby, both of which aresubstantially impervious to air, means for pumping air between said deckand said hull, a partition extended from the lower edge of said hull andinclined upwardly to form a barrier between the inside of said hull andthe water, and a substantially rigid member, said rigid member beingadapted to limit the motion of said lower edge of said hull with respectto said deck.

2. The apparatus of claim 1 including means for use in adjusting theangle of inclination of said partition.

3. The apparatus of claim 1 wherein said rigid member is coupled to andpivotally supported with respect to said deck.

4. The apparatus of claim 2 wherein said partition is nonrigid.

5. The apparatus of claim 3 wherein said hull is nonrigid.

6. The apparatus of claim 1 wherein both said partition and said hullare nonrigid.

7. Floatable apparatus for use on bodies of water comprising an openbottomed hull and a deck supported thereby, both of which aresubstantially impervious to air, means for pumping air between said deckand said hull, said apparatus including an extendable partition securedabout the opening in said open bottomed hull, and means for raising saidpartition into said hull and for lowering same therefrom as desired.

8. The apparatus of claim 7 wherein said partition is nonrigid.

9. The apparatus of claim 7 wherein said hull is nonrigid.

10. The apparatus of claim 7 wherein both said parti tion and said hullare nonrigid.

11. The apparatus of claim 10 wherein said hull is supported by meanscomprising a compression member (46), means (48) for pivotallysupporting said compression member (46) to said deck (10') and to saidhull (40), and a tension member (50) secured between said hull (40) andsaid deck (10') the points at which said compression and tension members(46, 50') secure to said hull being substantially the same, and thepoints at which said compression and tension members (46, 50) secure tosaid deck (10') being in spaced apart relationship.

12. The apparatus of claim 11 including a tension member (62) one end ofwhich secures to said skirt (56) the other end thereof being adapted forcoupling to a part of said floatable apparatus within the confines ofsaid hull (40).

References Cited UNITED STATES PATENTS 6/1966 Williams et a1. -1276/1968 Fresh et al. 180-127 US. Cl. X.R. 180l26, 127

